Flat Prismatic Components For Kinematics
In kinematic applications, plane flat surfaces have a higher load carrying capacity than cylindrical or spherical ones. Flat surfaces with very fine surface texture are quite slippery, so they provide excellent alignment of the mating spheres. Producing high quality flat planes on prismatic devices requires a unique approach. Lapping the inside flat faces of a Vee Block or even worse the inside faces of a Trihedral Cup is not at all a practical task.
An approach that can produce the highest quality internal prismatic devices is the split design. Instead of constructing the device as a monolith, which is conventional wisdom, each facet of the prism is produced as a separate but symmetrical unit.
A very high quality flat facet can be easily produced on the truncated surface of a cylindrical post. Rigidity is not lost by splitting the faces of the prism, because the cylindrical design provides a simple method for extremely rigid mounting. By machining a trench in the Kinematic Platform with an end mill that has the same radius as the cylindrical post itself, and gluing the assembly together under load, an extremely rigid assembly results. The reason that this design can so far outstrip the rigidity of a monolithic component is not so obvious; but it is due to the inherent weakness in the joint connecting the monolith to the Kinematic Platform.
For light loads, there is seldom any reason to use this more complicated flat facet design when three spheres will form an excellent trihedral cup and two cylinders a fine Vee Block.
A universal component that will fill a broad array of high load kinematic applications is a three-quarter inch diameter (19mm) cylindrical post that is truncated at a 45-degree angle. This one component will function well with any ball size from one half inch (13mm) to over one inch (25.4mm). Better repeatability can be achieved by using a steeper angle but this will reduce the load carrying capacity.
These components can be produced for surface mounting by drilling and threading a hole in the flat base but in doing so much of the system's rigidity is lost.< Because the relative cost of raw material is rather small in relation to the overall cost of this component, tungsten-carbide, with its tremendous stiffness--or Young's modulus of elasticity of 98,000,000 P.S.I. and high hardness of 91-HRA--has been chosen as the standard material.
There is wide latitude of design options of both size and materials to cope with different loads, corrosive environments, temperature, as well as magnetic and electrical qualities. We will custom build just about any design to fill specific customer needs.
The average price for a steel Prismatic Post is $45.00 each.
For prices and options, see: Monolithic Trihedral.
Monolithic Trihedral — Kelvin Clamp
Monolithic Trihedral, Part# TRH-75-SM
Monolithic Trihedral, Part# TRH-2000-SM
We are now producing two standard sizes of the Monolithic Trihedral kinematic component. They are designed for a surface mount. This trihedral is frequently referred to as a Kelvin Clamp. These devices are constructed from a very fine-grain, high-carbon, high-chrome stainless-steel that is through-hardened to 58-HRC minimum. The typical application for this component is to constrain three degrees of freedom in a Kelvin-type kinematic-coupling. This devices is the technically-correct approach for this coupling, whereas the commonly thought-of conical-cups are a very low quality over-constrained approach to achieving this coupling.
In this application, the Trihedral is used in conjunction with a vee-block and a flat surface, combined with three balls or spherical surfaces to complete the coupling. The smallest of these off the shelf Monolithic Trihedrals is our Part# TRH-75-SM. It is used in conjunction with our VB-75-SM or VB-75-CPM (surface or post-mounted Veeblock) and flat a component (see our literature for design criteria and price). This combination can be used with balls ranging from 5/8-inch (.625", 15.9mm) to 1.0 inch (25.4mm) diameter.
This device has a three-eighths-inch-sixteen threaded hole going through the center (3/8”, .375”, 9.525mm). This facilitates using our standard 3/8-inch rare-earth magnet (part # 375-24-MG-N) to provide an axial preload. The largest of these off the shelf Monolithic Trihedrals is our Part# TRH-2000-SM. This is used in conjunction with our VB-2000-SM or VB-2000-CPM (Vee Block) and flat component (see our literature for design criteria and price). This combination can be used with balls ranging from 1-1/4 inch (1.25”, 31.75mm) diameter to over 2-inches (50.8mm) diameter. This large-size trihedral has a unique feature, there is a one inch diameter (25.4mm), threaded-hole through the center of the base. This facilitates using our standard 1-inch by 14-thread (25.4mm) rare-earth magnet (Part #1000-14-MG-N) to provide a preload (see our literature for design criterion and pricing). The hole through the center of this large trihedral allows for a payload to hang with the load-carrying shaft passing through the center hole.
Some reasons for using the Kelvin-type kinematic coupling instead of the much simpler and less expensive Maxwell system consisting of three vees and three balls, is in the case that one single point on the payload must stay in exactly the same location during temperature changes (the point held by the Trihedral). Another is that rotary-adjustments need to be made around one specific point (the point held by the Trihedral). This is a typical requirement in optical systems where a laser or other light source must be accurately and precisely pointed or directed to the optical-axis of a system.
The Kelvin kinematic system is excellent for vertical and other off-axis kinematic couplings.
One last design trick: the simple combination of a Trihedral and a Veeblock form an excellent Kinematic hinge that will accurately constrain five degrees of freedom, leaving one single degree of rotation.
Trihedral Pricing
| Part # |
Description |
Price |
| 1000-14-MG-N |
MAGNETICALLY PRELOADED KINEMATIC COUPLING, NORTH |
$36.19 |
| 1000-14-MG-S |
MAGNETICALLY PRELOADED KINEMATIC COUPLING, SOUTH |
$36.19 |
| TRH-2000-SM |
MONOLITHIC TRIHEDRAL, 2" DIAMETER |
$218.00 |
| TRH-75-SM |
MONOLITHIC TRIHEDRAL, 0.75", 3/4" |
$108.00 |
| VB-2000-CPM |
VEE BLOCK, 2" CYLINDRICAL POST MOUNTED |
$173.00 |
| VB-2000-SM |
VEE BLOCK, 2" SURFACE MOUNTED |
$173.00 |
| VB-75-CPM |
VEE BLOCK, 0.750" ( 3/4" ), CYLINDRICAL POST MOUNTED |
$50.60 |
| VB-75-SM |
VEE BLOCK, 0.750" ( 3/4" ), SURFACE MOUNTED |
$50.60 |
For prices and options, see: Monolithic Trihedral.
Monolithic Trihedral — Kelvin Clamp
Monolithic Trihedral, Part# TRH-75-SM
Monolithic Trihedral, Part# TRH-2000-SM
We are now producing two standard sizes of the Monolithic Trihedral kinematic component. They are designed for a surface mount. This trihedral is frequently referred to as a Kelvin Clamp. These devices are constructed from a very fine-grain, high-carbon, high-chrome stainless-steel that is through-hardened to 58-HRC minimum. The typical application for this component is to constrain three degrees of freedom in a Kelvin-type kinematic-coupling. This devices is the technically-correct approach for this coupling, whereas the commonly thought-of conical-cups are a very low quality over-constrained approach to achieving this coupling.
In this application, the Trihedral is used in conjunction with a vee-block and a flat surface, combined with three balls or spherical surfaces to complete the coupling. The smallest of these off the shelf Monolithic Trihedrals is our Part# TRH-75-SM. It is used in conjunction with our VB-75-SM or VB-75-CPM (surface or post-mounted Veeblock) and flat a component (see our literature for design criteria and price). This combination can be used with balls ranging from 5/8-inch (.625", 15.9mm) to 1.0 inch (25.4mm) diameter.
This device has a three-eighths-inch-sixteen threaded hole going through the center (3/8”, .375”, 9.525mm). This facilitates using our standard 3/8-inch rare-earth magnet (part # 375-24-MG-N) to provide an axial preload. The largest of these off the shelf Monolithic Trihedrals is our Part# TRH-2000-SM. This is used in conjunction with our VB-2000-SM or VB-2000-CPM (Vee Block) and flat component (see our literature for design criteria and price). This combination can be used with balls ranging from 1-1/4 inch (1.25”, 31.75mm) diameter to over 2-inches (50.8mm) diameter. This large-size trihedral has a unique feature, there is a one inch diameter (25.4mm), threaded-hole through the center of the base. This facilitates using our standard 1-inch by 14-thread (25.4mm) rare-earth magnet (Part #1000-14-MG-N) to provide a preload (see our literature for design criterion and pricing). The hole through the center of this large trihedral allows for a payload to hang with the load-carrying shaft passing through the center hole.
Some reasons for using the Kelvin-type kinematic coupling instead of the much simpler and less expensive Maxwell system consisting of three vees and three balls, is in the case that one single point on the payload must stay in exactly the same location during temperature changes (the point held by the Trihedral). Another is that rotary-adjustments need to be made around one specific point (the point held by the Trihedral). This is a typical requirement in optical systems where a laser or other light source must be accurately and precisely pointed or directed to the optical-axis of a system.
The Kelvin kinematic system is excellent for vertical and other off-axis kinematic couplings.
One last design trick: the simple combination of a Trihedral and a Veeblock form an excellent Kinematic hinge that will accurately constrain five degrees of freedom, leaving one single degree of rotation.
Trihedral Pricing
| Part # |
Description |
Price |
| 1000-14-MG-N |
MAGNETICALLY PRELOADED KINEMATIC COUPLING, NORTH |
$36.19 |
| 1000-14-MG-S |
MAGNETICALLY PRELOADED KINEMATIC COUPLING, SOUTH |
$36.19 |
| TRH-2000-SM |
MONOLITHIC TRIHEDRAL, 2" DIAMETER |
$218.00 |
| TRH-75-SM |
MONOLITHIC TRIHEDRAL, 0.75", 3/4" |
$108.00 |
| VB-2000-CPM |
VEE BLOCK, 2" CYLINDRICAL POST MOUNTED |
$173.00 |
| VB-2000-SM |
VEE BLOCK, 2" SURFACE MOUNTED |
$173.00 |
| VB-75-CPM |
VEE BLOCK, 0.750" ( 3/4" ), CYLINDRICAL POST MOUNTED |
$50.60 |
| VB-75-SM |
VEE BLOCK, 0.750" ( 3/4" ), SURFACE MOUNTED |
$50.60 |
For prices and options, see: Monolithic Trihedral.
Monolithic Trihedral — Kelvin Clamp
Monolithic Trihedral, Part# TRH-75-SM
Monolithic Trihedral, Part# TRH-2000-SM
We are now producing two standard sizes of the Monolithic Trihedral kinematic component. They are designed for a surface mount. This trihedral is frequently referred to as a Kelvin Clamp. These devices are constructed from a very fine-grain, high-carbon, high-chrome stainless-steel that is through-hardened to 58-HRC minimum. The typical application for this component is to constrain three degrees of freedom in a Kelvin-type kinematic-coupling. This devices is the technically-correct approach for this coupling, whereas the commonly thought-of conical-cups are a very low quality over-constrained approach to achieving this coupling.
In this application, the Trihedral is used in conjunction with a vee-block and a flat surface, combined with three balls or spherical surfaces to complete the coupling. The smallest of these off the shelf Monolithic Trihedrals is our Part# TRH-75-SM. It is used in conjunction with our VB-75-SM or VB-75-CPM (surface or post-mounted Veeblock) and flat a component (see our literature for design criteria and price). This combination can be used with balls ranging from 5/8-inch (.625", 15.9mm) to 1.0 inch (25.4mm) diameter.
This device has a three-eighths-inch-sixteen threaded hole going through the center (3/8”, .375”, 9.525mm). This facilitates using our standard 3/8-inch rare-earth magnet (part # 375-24-MG-N) to provide an axial preload. The largest of these off the shelf Monolithic Trihedrals is our Part# TRH-2000-SM. This is used in conjunction with our VB-2000-SM or VB-2000-CPM (Vee Block) and flat component (see our literature for design criteria and price). This combination can be used with balls ranging from 1-1/4 inch (1.25”, 31.75mm) diameter to over 2-inches (50.8mm) diameter. This large-size trihedral has a unique feature, there is a one inch diameter (25.4mm), threaded-hole through the center of the base. This facilitates using our standard 1-inch by 14-thread (25.4mm) rare-earth magnet (Part #1000-14-MG-N) to provide a preload (see our literature for design criterion and pricing). The hole through the center of this large trihedral allows for a payload to hang with the load-carrying shaft passing through the center hole.
Some reasons for using the Kelvin-type kinematic coupling instead of the much simpler and less expensive Maxwell system consisting of three vees and three balls, is in the case that one single point on the payload must stay in exactly the same location during temperature changes (the point held by the Trihedral). Another is that rotary-adjustments need to be made around one specific point (the point held by the Trihedral). This is a typical requirement in optical systems where a laser or other light source must be accurately and precisely pointed or directed to the optical-axis of a system.
The Kelvin kinematic system is excellent for vertical and other off-axis kinematic couplings.
One last design trick: the simple combination of a Trihedral and a Veeblock form an excellent Kinematic hinge that will accurately constrain five degrees of freedom, leaving one single degree of rotation.
Trihedral Pricing
| Part # |
Description |
Price |
| 1000-14-MG-N |
MAGNETICALLY PRELOADED KINEMATIC COUPLING, NORTH |
$36.19 |
| 1000-14-MG-S |
MAGNETICALLY PRELOADED KINEMATIC COUPLING, SOUTH |
$36.19 |
| TRH-2000-SM |
MONOLITHIC TRIHEDRAL, 2" DIAMETER |
$218.00 |
| TRH-75-SM |
MONOLITHIC TRIHEDRAL, 0.75", 3/4" |
$108.00 |
| VB-2000-CPM |
VEE BLOCK, 2" CYLINDRICAL POST MOUNTED |
$173.00 |
| VB-2000-SM |
VEE BLOCK, 2" SURFACE MOUNTED |
$173.00 |
| VB-75-CPM |
VEE BLOCK, 0.750" ( 3/4" ), CYLINDRICAL POST MOUNTED |
$50.60 |
| VB-75-SM |
VEE BLOCK, 0.750" ( 3/4" ), SURFACE MOUNTED |
$50.60 |
For prices and options, see: Monolithic Trihedral.
Monolithic Trihedral — Kelvin Clamp
Monolithic Trihedral, Part# TRH-75-SM
Monolithic Trihedral, Part# TRH-2000-SM
We are now producing two standard sizes of the Monolithic Trihedral kinematic component. They are designed for a surface mount. This trihedral is frequently referred to as a Kelvin Clamp. These devices are constructed from a very fine-grain, high-carbon, high-chrome stainless-steel that is through-hardened to 58-HRC minimum. The typical application for this component is to constrain three degrees of freedom in a Kelvin-type kinematic-coupling. This devices is the technically-correct approach for this coupling, whereas the commonly thought-of conical-cups are a very low quality over-constrained approach to achieving this coupling.
In this application, the Trihedral is used in conjunction with a vee-block and a flat surface, combined with three balls or spherical surfaces to complete the coupling. The smallest of these off the shelf Monolithic Trihedrals is our Part# TRH-75-SM. It is used in conjunction with our VB-75-SM or VB-75-CPM (surface or post-mounted Veeblock) and flat a component (see our literature for design criteria and price). This combination can be used with balls ranging from 5/8-inch (.625", 15.9mm) to 1.0 inch (25.4mm) diameter.
This device has a three-eighths-inch-sixteen threaded hole going through the center (3/8”, .375”, 9.525mm). This facilitates using our standard 3/8-inch rare-earth magnet (part # 375-24-MG-N) to provide an axial preload. The largest of these off the shelf Monolithic Trihedrals is our Part# TRH-2000-SM. This is used in conjunction with our VB-2000-SM or VB-2000-CPM (Vee Block) and flat component (see our literature for design criteria and price). This combination can be used with balls ranging from 1-1/4 inch (1.25”, 31.75mm) diameter to over 2-inches (50.8mm) diameter. This large-size trihedral has a unique feature, there is a one inch diameter (25.4mm), threaded-hole through the center of the base. This facilitates using our standard 1-inch by 14-thread (25.4mm) rare-earth magnet (Part #1000-14-MG-N) to provide a preload (see our literature for design criterion and pricing). The hole through the center of this large trihedral allows for a payload to hang with the load-carrying shaft passing through the center hole.
Some reasons for using the Kelvin-type kinematic coupling instead of the much simpler and less expensive Maxwell system consisting of three vees and three balls, is in the case that one single point on the payload must stay in exactly the same location during temperature changes (the point held by the Trihedral). Another is that rotary-adjustments need to be made around one specific point (the point held by the Trihedral). This is a typical requirement in optical systems where a laser or other light source must be accurately and precisely pointed or directed to the optical-axis of a system.
The Kelvin kinematic system is excellent for vertical and other off-axis kinematic couplings.
One last design trick: the simple combination of a Trihedral and a Veeblock form an excellent Kinematic hinge that will accurately constrain five degrees of freedom, leaving one single degree of rotation.
Trihedral Pricing
| Part # |
Description |
Price |
| 1000-14-MG-N |
MAGNETICALLY PRELOADED KINEMATIC COUPLING, NORTH |
$36.19 |
| 1000-14-MG-S |
MAGNETICALLY PRELOADED KINEMATIC COUPLING, SOUTH |
$36.19 |
| TRH-2000-SM |
MONOLITHIC TRIHEDRAL, 2" DIAMETER |
$218.00 |
| TRH-75-SM |
MONOLITHIC TRIHEDRAL, 0.75", 3/4" |
$108.00 |
| VB-2000-CPM |
VEE BLOCK, 2" CYLINDRICAL POST MOUNTED |
$173.00 |
| VB-2000-SM |
VEE BLOCK, 2" SURFACE MOUNTED |
$173.00 |
| VB-75-CPM |
VEE BLOCK, 0.750" ( 3/4" ), CYLINDRICAL POST MOUNTED |
$50.60 |
| VB-75-SM |
VEE BLOCK, 0.750" ( 3/4" ), SURFACE MOUNTED |
$50.60 |
For prices and options, see: Monolithic Trihedral.